The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Mar. 27, 1990

Filed:

Mar. 20, 1989
Applicant:
Inventors:

Kenji Takato, Kawasaki, JP;

Toshiro Tojo, Kawasaki, JP;

Kazumi Kinoshita, Kawasaki, JP;

Yuzo Yamamoto, Kawasaki, JP;

Assignee:

Fujitsu Limited, Kawasaki, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H23F / ;
U.S. Cl.
CPC ...
330261 ; 379395 ;
Abstract

An operational amplifier for producing an output signal representing the voltage differential between two input signals is powered by first, second and third power sources respectively having high, intermediate and low output voltage levels. A voltage buffer circuit, which is connected to the second power source, interconnects a constant current source, which is connected to the first power source, and an amplifier means, which is connected to the third power source, and separates the constant current source from the third power source. A differential amplifier in the amplifier means responds to the two input signals for producing a voltage differential output signal, and an output circuit connected between the second and third power sources receives the voltage differential output signal of the differential amplifier for producing the voltage differential output signal of the operational amplifier.


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